Heretofore, such as shown in U.S. Pat. No. 5,005,830 dated Apr. 16, 1991, exercise machines have been provided for testing and exercising lumbar or abdominal muscles of a user or patient. In such machines, the user is strapped in a seated position and then force is applied in a generally horizontal direction against the femurs of a user to push the femurs rearwardly and downwardly for anchoring the pelvis and preventing any movement of the pelvis during testing and exercising. In order to detect any movement of the pelvis during an exercise or test, a measuring device is connected to a rear pelvic pad contacting the body of the user. If any movement of the user is detected, the restraining straps are tightened and additional force is applied against the femurs. The application of such a strapping or pushing force against the femurs sufficient to prevent any movement of the pelvis during exercising or testing provides discomfort to the user and also requires substantial time in order to insure that no movement of the pelvis occurs during testing and exercising.
An actuating or movement arm in the '830 patent is mounted for pivotal movement about a horizontal axis and has a pad engaged by the upper back of a user with a weight resistance operatively connected to the movement arm. The movement arm is contacted by the user's back and a back and forth bending movement of the upper torso of the user exerted against the back pad effects pivotal movement of the movement arm. In anchoring or preventing movement of the pelvis during testing and exercising, the lumbar muscles are isolated. A strain gauge is provided for measuring the static strength of the lumbar muscles in each of different angular positions of the spine. The strain gauge is not anchored to the fixed frame, but instead is mounted for movement with the movement arm during the entire testing and exercising program. During static testing, the strain gauge is tensioned between the movement arm and a sprocket which is releasably locked to the fixed supporting frame to prevent movement of the sprocket.